Scientists develop way to supercool liquids without freezing them

Scientists proved their novel supercooling technique could be used to preserve red blood cells for 100 days.

Researchers say their technology could be used to improve the preservation of blood and other biological samples. Photo by Steve Collender/Shutterstock

Aug. 10 (UPI) -- Researchers at the Massachusetts General Hospital Center for Engineering in Medicine have developed a new way to supercool liquids without freezing them.

Scientists used the method to significantly decrease the freezing points of water and water-based solutions, allowing them to keep the liquids at extremely cold temperatures for a long period of time.

To prevent freezing, scientists relied on insulation.

"Our approach, which we dubbed 'deep supercooling,' is simply to cover the surface of such a liquid with a solution that does not mix with water, like mineral oil, to block the interface between water and air, which is the major site of crystallization," researcher Berk Usta said in a news release. "This surprisingly simple, practical and low-cost approach to supercooling solutions for extended periods can enable many medical and food preservation methods, as well as fundamental experiments that were not previously possible."

As previous research has shown, the formation and growth of ice crystals is triggered by impurities -- pieces of dust or bacteria -- at the water-air interface.

Traditional supercooling attempts have relied on high pressure, which can damage biological samples, and involved only small amounts of liquid kept at subzero temperatures for short amounts of time.

During their first round of experimentation, scientists sealed small samples of water and water-based solution with basic hydrocarbon-based oils, including mineral oil, olive oil and paraffin oil. The researchers succeeded at keeping the samples' temperatures as low as negative 13 degrees Celsius for up to a week.

In followup experiments, scientists improved upon their initial results using more complex oils, as well as pure simple hydrocarbons like alcohols and alkanes. The researchers were able to supercool small samples to negative 20 degrees Celsius and maintain the subzero temperatures for 100 days. The scientists were able to keep larger samples at similarly frigid temperatures for a week.

The team of scientists proved their novel supercooling technique could be used to preserve red blood cells for 100 days. Under normal storage conditions, cell quality begins to decline after two weeks.

"Along with potential applications in medicine and food preservation, we also believe this invention could be used to study chemical reactions in the liquid state at low temperatures without the usual costly and complicated high-pressure equipment," Usta said.